Mixxx - The most powerful free DJ software in the world.
Youtube-DJ - Mix YouTube songs together
VirtualDJ - Virtual DJ Software - MP3 and Video mix software for DJs
Pacemaker - Create and share mixtapes with friends
Traktor Pro - Flagship DJ software with four decks and a stunning range of creative features for maximum freedom in DJing.
djay Pro for iPad - djay Pro provides a complete toolkit for performing DJs.